Sunlight Might Have Been the Catalyst for Life on Earth

A new study suggests that ultraviolet light (a.k.a sunlight) might have been one of the three crucial ingredients that produced the enzymes that essentially made life on Earth possible.

UV light, along with primitive biomolecules and iron salts, is now believed to be the catalyst that led to the formation of the iron-and-sulfur clusters floating atop Earth’s oceans. These enzymes make everything from cellular respiration to DNA repair possible and, without the enzymes, living beings would not be able to generate or retain energy.

In the early years of our planet’s history, Earth lacked an ozone layer to protect its surface from the effects of UV light—the effects of which were much more intense and harmful billions of years ago. That being the case, it would only make sense that some form of UV light or affects from the sun’s rays would have something to do with the early synthesis of the compounds that make up everything around us.

In fact, as Science Magazine reports, a team of scientists recreated the conditions of early Earth in order to test various combinations of sulfur-containing molecules under exposure to UV light and mixtures of various other compounds. Essentially, they found that the iron-sulfur clusters synthesized in roughly the same manner as modern living cells do under the same conditions.

Though the knowledge of this reaction is a huge step forward in figuring out the origins of life on Earth, scientists cannot definitively state that any such reactions occurred without further conclusive evidence.